<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    手机号码： <input type="number"> <button>发送</button>
    <script>
 var input = document.querySelector('input');
        var btn = document.querySelector('button');
   
        var lasttime = 60;
      
        btn.addEventListener('click', function() {
         
            var timer = setInterval(function() {
            
                if (lasttime == 0) {
            
                    clearInterval(timer)
                    btn.disabled = false;
                    btn.innerText = '发送';
                    lasttime = 3;
                } else {
                    btn.disabled = true;
                    btn.innerText = '离下次发送短信还剩下' + lasttime + '秒';
                    lasttime--;
                }
            }, 1000)
        })
    </script> 
</body>
</html>